The field of the present invention is adjustable mounts for electrical devices.
Landscape lighting fixtures have traditionally been faced with significant challenges in precise aiming of such fixtures. Adjustment devices used to aim the fixtures must endure the rigors of being mounted in the ground where abuses from maintenance, fertilizer, water, mud, debris, vandalism, and weather extremes are commonplace. Furthermore, the mechanisms commonly are asked to articulate in multiple axes, along with being capable of routing electrical wires through the articulation. This challenge is compounded when water tightness is a requirement.
Existing mechanisms used to mount, adjust and aim these types of fixtures include knuckle joint assemblies and yoke or stirrup assemblies. Knuckle joint assemblies are comprised of two mating halves fixed about a central pivot point. This pivot point usually is a screw which, when tightened, locks the two halves together. Knuckle joint assemblies are affixed to the lighting fixture at a single point. Electrical supply is commonly routed through the knuckle joint assembly. To avoid loss of alignment, intermeshed teeth on mating halves have been used. The fineness of the meshed teeth determine aimability of the fixture. Tapered conical mating features also have been used to eliminate the indexing of the aiming limitations inherent with using teeth. Conical tapers rely solely on friction to overcome rotational forces, but can become frozen in place.
Routing wiring through the single pivot knuckle assembly usually results in chafing of the wiring. Because knuckles tend to be relatively small, tight spacing magnifies the chafing. Shorting of the wring is commonplace in this area and is usually a mode of failure for this type of fixture. Twisting of the wiring around the pivot point screw is another issue with electrical pass through routing. Adjustments where the fixture is articulated about the centerline of the knuckle stem also strains the electrical supply connections. This adjustment is generally accomplished through a standard male threaded pipe stem assembled into a female threaded hub opening. If aiming requires the position of the fixture to be different than where the male/female joint tightens, the stem can remain loose.
Knuckle joint assemblies usually have no provision to block water entry directly into the fixture from the electrical pathway. Seals such as O-rings are often damaged or crushed as the fixture is adjusted. Wiring routed into the fixture is loose and openings allowing the electrical entry into the fixture body are generally not sealed.
Yoke or stirrup type assemblies are typically affixed to the lighting fixture at two pivot points located along an axis about which the fixture pivots. Adjustment is effected when the two pivot point mechanisms are loosened, the fixture aimed, then the two pivot point mechanisms are tightened. There is typically no provision for internal electrical routing. The electrical penetration into the fixture housing must be done separately which adds another point of water entry and does not allow for clean second axis rotation. Further, the electrical connections are accessible and, therefore, subject to exposure and vandalism. If rotation and electrical supply pass through are combined at one point, that point requires separate sealing as well as a mechanism for locking the position of the fixture.